<!DOCTYPE html>
<html lang="zh-CN">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
    <style>
      .box {
        width: 400px;
        height: 400px;
        border: 1px solid black;
        background: url("../../images/lt.png") no-repeat left top,
          url("../../images/rt.png") no-repeat right top,
          url("../../images/lb.png") no-repeat left bottom,
          url("../../images/rb.png") no-repeat right bottom;
      }
    </style>
  </head>
  <body>
    <div class="box"></div>
  </body>
</html>
